All of the options are motivations for the European imperialism, except for C.
As European countries grew more and more industrialized as many inventions and technological improvements came up, they needed more natural resources and raw materials, and became fully capitalist economies where competition is the base of the system's operation.
Industrialization changed completely cities, the countryside and the dynamics between them. City factories along with closures in England, for example, caused a flowing of people from the countryside into cities, creating plenty of available labor and a new world of work. There was no need for immigrant labor.